Electrode for high-pressure mercury-vapor discharge device



r Oct. 8, 1940. I v J. FRANCIS- 2,217,438

ELECTRODE FOR HIGH-PRESSURE MERCURY-VAPOR DISCHARGE DEVICE Filed 001:. 17, 1938 Inventor: Victcm J. Francis,

9 lfi i Attorneg.

' Patented Oct. 8, 1940 maps FOR- HIGH-PRESSURE MER- OR DISCHARGE DEVICE North Wembley, Englan Electric Company, a cor- ELECTRODE CU Victor James Francis, assignor to General poration of New York October 17, 1938, Serial No. 235,483

at Britain October 18, 1937 4 Claims. (01. 176-126) and 6 mm. 1 a sintered mixture of th der; part II is a r material 0.8 mm. helix 3 of tungsten wire, a 0.8 mm. mand of part II being 4 mm.; tungsten wire .4 mm. in diamete on a mandrel 1.4 mm. covers the whole of t mm. along the part I, there firmly. The electrode struc the discharge envelope 8 by means 0 sion 1 of the helix 6.

Such an electrode s H. P, M. V. lamps consu volts between runnin Having now particu tained the nature of my sa what manner the same is declare that what I claim is: 1. An electric discharge devic ates to high-pressure metalarge (H. P. M. V.) devices lectrode structureg electrode (in cut specification No.

echanically inect is to provide improved his kind, the chief qual- 1 size and simplicity of This invention rel vapor electric disch of the type comprising an e wherein a starting and a the sense of British pat 472,658) are parts of tegral body. Its obj electrode structures of t ities sought being smal construction.

It is pointed out in Br No. 486,138 that, with s running electrodes, it i tions in which the disch tially, but not wholly, starting electrode continues during one half of running electrode a 0d 2 of thermio in diameter, supported by a 0.3 mm. in diameter the same in rel, the over-all length part III is a helix 6 of r, close-wound in diameter. This helix 6 he part II and extends 3 by uniting these parts ture is supported in itish patent specification f starting and s possible to find condiarge transfers itself parduring the run up; the to act as the cathode le, but the associated cts as the anode during the des in which such partial t within the scope ome kinds 0 tructure is suitable for miiig 250 watts with trodes 35 mm. apart. larly described and ascerid invention and in transference takes place are no to be performed, I of this invention.

According to the inve device of the type s structure comprises (I ducting material (prcfera mixed with tungsten powder body consisting wholly or pa ically active 111 than the said re sleeveliiie metal body un to end. The parts I nearly the same diame of the known si kaline earth compoun helix, or a plurality 0 other, of refractory m rounding the active ma body III is preferably a re in order that it sha helix forming part 0 be provided with a store material which is as eas forming part or the whole of t II is unnecessary. The part I is turned towards the di trade is some part of covering the body II or self. The whole electrode may behind, preferably by means of the wire constitutin One embodiment of an elevation-a1, partly s mpanying d d l, 1.4 mm. in diameter e comprising a onizable me 0d of refractory ted body consistically active mae than the said repporting said rod ody in end-to-end relation, g a sleevelike member of nds and externtion in an'H. P. M. V. fled, the said electrode a rod of refractory conbly tungsten or thoria (Ii) an elongated rtly of thermioneasily vaporizable fractory metal, (III) a porous iting parts I and II end sealed envelope containing an i and. an electrode comprising a conducting material, an elonga ing wholly or partly of the terial more easily vaporizabl fractory material an and said elongated b said means comprisin porous char nally' engages 2. An electric adapted to opera pressure compris a vaporizable me a rod of refractory con gated body consisting w mionically active mat able than the said refra supporting said rod an end-to-end relation, refractory metal helix rod and the body for a substantial their lengths. 4

3. An .electric disc adapted to oper pressure compris a vaporizable me a rod of refractory conducting d helix having in con e material more easily vaporaterial more acter which. surrou both the rod and the body.

discharge device of the type te with a relatively high vapor ing a sealed envelope containing tal and an electrode comprisin ducting material, an elonholly or partly of theral more easily vaporizctory material, and means d said elongated body in id means comprising a which surrounds both the electrode and is scharge; the starting electhe porous metal part III possibly the body II itbe supported from of a prolongation the running harge device of the type ate with a relatively high vapor ing a sealed envelope containing tal and an electrode comprising material and an tact therewith I thermionically activ izable 'than the said ref refractory metal helix un elongated helix end-to-end.

the invention is shown in ectional view by way of rawing. Here ractory material and a example in the acco iting said rod and said part I is a tungsten ro ong, the outer end-being coated with oria and tungsten pownically active 4. An electric discharge device including a terial, and means supporting said rod and said sealed envelope containing an ionizable medium elongated helix in end-to-end relation, said and an electrode within the envelope; said e1ec' means comprising a. refractory metal helix which trode comprising a rod of refractory-conductive surronnds and externally engages both the rod material, an elongated helix having in contact and the elongated helix for a substantial portion 5 therewith thermionically active material more of their lengths. easily vaporizable than the said refractory ma- VICTOR JAMES FRANCIS. 

